1. Field of the Invention
The present invention relates to a horizontal multi-material molding machine in which a multi-material molding metal mold is mounted on a rotary table having a rotation axis center in a horizontal direction.
2. Description of the Related Art
Multi-material (multi-color) molding machines, which mold a composite multi-molded or multi-color-molded product using a plurality of types or a plurality of colors of resins, are known. There are a vertical rotary injection molding machine (for example, Jpn. Pat. Appln. KOKAI Publication Nos. 6-91688 and 10-264200) and a horizontal injection molding machine (for example, Jpn. Pat. Appln. KOKAI Publication No. 6-55569) as these multi-material molding machines.
In the vertical rotary injection molding machine, a stationary metal mold composed of a plurality of injection molding metal molds is fixed on a stationary die, a movable metal mold is fixed on a rotary table, and the movable metal mold is alternately confronted with the stationary metal mold by the rotation of the rotary table. The vertical rotary injection molding machine is arranged such that the rotary table has a rotation axis center in a vertical direction and is rotated in a horizontal plane.
A drive source of the vertical rotary injection molding machine is a servo motor which stops when the rotary table reaches a set rotation angle by an encoder and a control unit, thereby the rotary table is stopped at a predetermined position.
In the horizontal injection molding machine, two injection devices are disposed on the upper surface of a rotary table in directions 180° apart from each other, the rotary table is rotated by a rotation mechanism, and molding is executed by alternately moving the two injection devices to an injecting position. The horizontal injection molding machine is also arranged such that the rotary table has a rotation axis center in a vertical direction and the rotary table is rotated in a horizontal plane.
A drive source of the horizontal injection molding machine is a hydraulic motor, and a pin as a positioning mechanism is inserted into a pin hole of the rotary table, thereby the rotary table is kept at a stop position.
Each of the vertical rotary injection molding machine and the horizontal injection molding machine described above is arranged such that the rotation axis center of the rotary table extends in the vertical direction and the rotary table is rotated in the horizontal plane. Accordingly, when the rotary table is stopped because the drive source stops, the rotary table is kept at the stop position.
In contrast, there is used a horizontal injection molding machine having a rotation axis center in a horizontal direction. In this horizontal injection molding machine, a metal mold mounting surface of a rotary table is formed in a vertical direction. Moreover, since a heavy injection molding metal mold is fixed on the metal mold mounting surface of the rotary table, when a motor which rotates the rotary table stops or is stopped by power failure and the like, the motor becomes free to rotate, from which a problem arises in that the rotary table is rotated by gravity.